It is known to provide an electric machine having a substantially circular stator and a coaxial rotor rotatably mounted within the stator. A wide variety of designs are known including the switched reluctance motor (SRM), permanent magnet synchronous motor (PMSM), doubly salient permanent magnet (DSPM) motor, induction motor and wound field motor. The DSPM motor is a SRM motor incorporating permanent magnets (PMs) into the switched reluctance structure.
SRM-type motors are of particular interest for use in electric vehicles (EVs) and hybrid electric vehicles (HEVs) due to good power density, robustness, fault tolerance and relatively low cost compared with permanent magnet (PM) machines.
It is desirable to provide improved electric machines for use in motor vehicles as propulsion motors, generators or combined motor/generators.